tabbing with jquery not working

Question

I wonder if users click "test 1" will add class active in sidebar anchor and add background to expand list "#bar1".

the result should be sidebar font will red, and expand list background will red

But,what I found here if I click "test 1" it wont add class to anchor. Please is there anyone can help me to correct my code

$(document).ready(function(){
  $('.sidebar li a').click(function(e){
    e.preventDefault();
    $(this).addClass('active');
    $(this).removeClass('active');
    var exId=$(this).attr('href');
    $(exId).addClass('expandBg');
    $(exId).siblings().removeClass('expandBg')
  })
});

a.active{
  text-decoration: none;
  color: #f00;
}

.expandBg{
  background-color:#f00;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="sidebar">
  <ul>
    <li><a href="#bar1">test 1</a></li>
    <li><a href="#bar2">test 2</a></li>
    <li><a href="#bar3">test 3</a></li>
    <li><a href="#bar4">test 4</a></li>
  </ul>
</div>

<div class="expand">
  <ul>
    <li id="bar1">bar1</li>
    <li id="bar2">bar2</li>
    <li id="bar3">bar3</li>
    <li id="bar4">bar4</li>
  </ul>
</div>

Answer 1

this line of code $(this).removeClass('active'); make an issue we want to remove active class from siblings anchor tag please find below snippet to know how to do that

$(document).ready(function(){
  $('.sidebar li a').click(function(e){
    e.preventDefault();
    debugger;
    $(this).addClass('active');
    $(this).parent().siblings().find("a").removeClass("active")
    var exId=$(this).attr('href');
    $(exId).addClass('expandBg');
    $(exId).siblings().removeClass('expandBg')
  })
});

a.active{
  text-decoration: none;
  color: #f00;
}

.expandBg{
  background-color:#f00;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="sidebar">
  <ul>
    <li><a href="#bar1">test 1</a></li>
    <li><a href="#bar2">test 2</a></li>
    <li><a href="#bar3">test 3</a></li>
    <li><a href="#bar4">test 4</a></li>
  </ul>
</div>

<div class="expand">
  <ul>
    <li id="bar1">bar1</li>
    <li id="bar2">bar2</li>
    <li id="bar3">bar3</li>
    <li id="bar4">bar4</li>
  </ul>
</div>